The invention relates to a splice between ends of multi-ply yarn, and to methods and apparatus for making such splices.
It is known to interconnect two ends of a thread without knots by methods which are frequently designated "splicing" and which operate on various principles (see ITB 3/81 Spinning, pages 281 to 290 and 312). In the case of pneumatic splicing, the two ends of the thread to be interconnected are intertwined by a blast of compressed air, such that a permanent splice is established (see also German Offenlegungsschrift No. 28 10 741 and German Offenlegungsschrift No. 29 39 481). In the case of electrostatic splicing, the ends of the thread are intertwined by electrical means, while, in the case of mechanical splicing (see German Offenlegungsschrift No. 29 42 385), the ends of the thread are interconnected by mechanical action by controlled displacement of components of the fiber groups to be interconnected.
These known methods produce satisfactory results when interconnecting the ends of single-ply yarn. However, it has been found that difficulties arise when applying these known methods to multi-ply yarn, and unsatisfactory results are frequently obtained.
Furthermore, a method of connecting two ends of a multi-ply yarn is known (British Patent Specification No. 991 229) in which a splice is obtained in which each ply end of an end of one multi-ply yarn is disposed adjacent to an associated ply end of an end of the other multi-ply yarn so as to overlap over a predetermined length, and each of these two ply ends has the other ply or the other plies of the multi-ply yarn wrapped around it in the region of overlap, different regions of overlap of a splice being disposed in the longitudinal direction of the multi-ply yarn without overlaps.
In the known method, the ply ends at the ends of the multi-ply yarn are separated manually and are held in a clamping device, and the two ends of the multi-ply yarns to be spliced are brought together parallel to the longitudinal direction of the multi-ply yarn to an extent that each ply end of the end portion of one multi-ply yarn overlaps a ply end of the end portion of the other multi-ply yarn. A ply end of the end portion of the one multi-ply yarn is then permanently fixed on an associated ply end of the end portion of the other multi-ply yarn in the region of overlap by compressed air turbulence, the device for creating compressed air turbulence being displaceable such that the regions of turbulence of different mutually associated ply ends do not overlap in the longitudinal direction of the multi-ply yarn. Finally, the free ply ends which are not twirled together are cut off. A twist in the same direction can be introduced into the two end portions of the multi-ply yarn at the end of the process.
The known method has the disadvantage that it is difficult to automate and necessarily requires the additional permanent fixing of the mutually associated ply ends by compressed air turbulence since, otherwise, the ends of the multi-ply yarn would not be securely interconnected, and the free ply ends might be extricated from the finished splice.
An object of the present invention is to provide, between two ends of multi-ply yarn, a splice of the type described above, which, on the one hand, is simple to produce and results in highly satisfactory strength and, on the other hand, in which it is unnecessary to provide special means, such as compressed-air turbulence, glueing, rubbing or the like to permanently fix the mutually associated ply ends in a manner which would considerably impair the uniform fiber structure. It is possible readily to automate the method of making such a splice.